Road joint



April 1953 w. s. eoowm 2,634,660

ROAD JOINT Filed Nov. 19, 1949 3 Sheets-Sheet l INVENTOR. William S. Godwin W. S. GODWlN April 14, 1953 ROAD JOINT 5 Sheets-Sheet 2 Filed NOV. 19, 1949 I m 4 0 T. NM m d V 0 m6 I v I H 57 W RNEY5 April 14, 1953 w. s. GODWIN ROAD JOINT I 3 Sheets-Sheet 5 Filed NOV. 19, 1949 INVENTOR. William 5. Godwin BY Patented Apr. 14, 1953 l ROAD JOINT William S. Godwin, Baltimore, Md. Application November 19, 1949, Serial No. 128,417

4 Claims.

The invention relates to road joints, and more particularly to dowel units for such joints and to the utilization of such dowel units in the construction of the joints.

This application represents an improvement on the arrangement shown in my prior application Serial No. 48,962, filed September 13, 1948, and now abandoned, and is in part a continuation of such prior application.

' Various proposals have been made for supporting road joint dowels and other mechanisms involved in the formation of joints in concrete roads while the concrete or other road material is being laid, but such proposals have involved the use of rather complex, heavy and expensive arrangements. Furthermore, various suggestions have been made for anchoring the dowels in the concrete, but the devices for this purpose have been complicated and expensive, and have ordinarily involved the use of long dowels.

- With the devices heretofore known, it has been difficult to obtain satisfactory transfer of the load from one concrete slab to the other. In the first place, the arrangements previously suggested have not been satisfactory for the proper positioning and spacing of the dowels. Again, the transfer of the load from the slab to the dowel or vice versa has not been adequate to distribute the strains throughout the slab, with the result that substantial stresses have been imposed on the concrete immediately at the face of the joint. This is likely to result in a short period of time in damage to the concrete by crushing, which reduces the contact between the dowel'and the concrete and thus substantially affects the efficiency of the transfer of the load from one slab to the other. In addition, the use Of'lOIlg dowels subjects the joint to the dangers of corrosion, and to the freezing of the dowels. When this happens, the dowel units no longer act properly, and cracks are created which destroy the road quite rapidly.

The primary object of the present invention is to provide a structure for anchoring a dowel in a concrete or other road joint which is economical to manufacture, which is light and sturdy and which is at the same time more effective. Such a device saves material, since it requires less steel than known units of much less efiiciency, and since it can be shipped more cheaply. Another object of the invention is to provide a device of this type which will support the dowel by holding it firmly in proper position as the road is laid and thereafter in the concreta z. y

will anchor it firmly Still another object of the invention is to provide a device of this type which can be used for both expansion and contraction joints.

An additional object of the invention is to provide an arrangement which, by securely anchoring the dowel, permits the use of shorter dowels for giving load transfer between adjacent slabs than was possible with the prior art devices. Such shorter dowels, together with the proper load distributing means, reduce substantially the stress on the concrete at the face of the joint.

At the same time, the surface area of the dowelis sufficiently reduced so that the likelihood of freezing and the resulting damage to the slab are almost entirely eliminated.

Still another object of the invention is to provide a device for distributing and reducing the intensified stress under and above the dowel adjacent the joint.

A further object of the invention is to provide a dowel supporting member which is self-adjust ing with respect to the dowel so that when dowels are placed in position through such supports on the subgrade they will automatically assume proper positions with respect to the supports. This construction reduces the danger that the dowel will be improperly aligned, or will be disturbed during the pouring of the road material. In addition, by virtue of this self-centering effect, a much simpler dowel supporting unit can be made, and this need not be manufactured with too great exactness to fit the size of the dowel.

More particularly in this respect the invention contemplates a construction which will make contact with the dowel at three points around its periphery, this support being adapted to engage the dowel close to the face of the joint and having extensions to distribute the stresses through the cement above and below the dowel. In the preferred form, the downward stress distributing member also serves to support the dowel unit above the subgrade during the pouring of the concrete.

I have found that it is most important that the stresses be transmitted away from the face of the joint into the road material above and below the dowel. By providing for the distribution of at least of the stress from the dowel, at a point adjacent the joint face, into the material in this way, it is possible to sustain much greater loads with short dowels, and to avoid damage to the dowels, by bending or otherwise.

It is another object of my invention to provide a unit which combines with a short dowel a stress distributing means which will distribute at least 65% of stress or load from the part of the dowel adjacent the joint into the material remote from the joint and above and below the dowel.

Still a further object of the invention is to provide devices and methods for the laying of the concrete joints utilizing dowel supporting units of the type contemplated herein.

More particularly, the invention contemplates an arrangement in which the self-centering structure 'of the dowel supporting units is used simultaneously to obtain a clamping effect on a joint forming member, either a bar in the case of a contraction joint or a filler strip in the case of an expansion joint, so as to hold the joint forming member steady during the pouring of the material of the roadway.

Further objects and advantages of the invention will appear more fully from the following description, especially when taken in connection with the drawings.

In the drawings:

Fig. 1 shows in side elevation a pair of dowel supporting units according to my invention with a dowel therein;

Fig. 2 shows'the two parts of which each dowel holding member is made up;

'Ffigs. 3 and 4 are cross-sections substantially on the lines 3-3 and l-4, respectively, of Fig. 1;

5 is a view from the right hand end of Fi 1;

Fig. 6 is a view similar to Fig. 1 showing a modified form of the invention;

7 shows in side elevation a joint forming arrangement for contraction joints utilizing dowel holders of the new type;

Fig. 8 is a cross-section substantially on the line 88 of Fig. 7;

Fig. 9 is a top plan view of this assembly;

Fig. 10 is a cross-section through a portion of a road joint at a later stage in its formation, utilizing the mechanism of Figs. '7 to 9;

Fig. 11 is a View similar to Fig. 7 showing the f rma io f an e pansi n J int;

Fig. 1 2 is a cross-section on the line l2l2 of Fi 11.;

13 is a. top plan view of the assembly; and

Fig. 14 is a cross-section through the joint SIlOwing the procedure at a later stage in its orma n.

Each dowel supporting member, as shown in Figs. 1 to 5, is formed of an upper part 2 and a lower part 4. Each of these parts is made preferably of a rod or heavy wire of steel, bent into substantially a U-shape. The two are secured together as for instance by welding 6 so as to intersect each other adjacent their bights, the parts lying in planes forming a substantial angle and preferably forming nearly a right angle, with each other.

Fig. 2 shows separately these two parts with a dowel 8 for comparison. It will be noted that the radius Of curvature of the bight of section 2 is somewhat less than that of the radius of curvature of dowel 8, while that of section 4 is somewhat greater. The two parts are secured together with section 2 inside section 4. As a result of this arrangement, there is formed as shown in Fig. 5, a passage through the two bights, the axis of this passage lying in a plane intersecting the crossing points of the two bights. Because the radius of curvature of the bight of part 2 is less than that of the dowel, the dowel engages the legs of this member only at two.

ppints I0 and I2 (Fig. 3) while the member 4 reas s he ow l on y at a Point 1.4 In other 4 words, there are three points of contact only between the dowel and the opposite member.

Preferably, but not necessarily, the lower member 4 is sufiiciently long to extend downward and support the dowel at the desired distance above the subgrade. When two of these supports are applied to the dowel in opposite directions, they form with the subgrade a supporting triangle for the dowel. Because of the three point suspension in each support, the dowel will adjust itself properly in the supports, in which itfits somewhat loosely, without the danger that it will be improperly positioned in the joint. Nevertheless, these supports hold the dowel so steadily that it will not be disturbed during the pouring of the concrete. In fact, such a dowel unit will easily sustain the weight of a heavy man. Yet when it is merely set on the ground, it clamps the dowel so steadily that it is impossible even to turn the dowel in the units.

The members 2 and 4 also extend from their points of engagement with the dowel into the concrete above and below the dowel, and ,ba wardly and outwardly from the face of the i0; Ht. By means of the three point suspension, the loads are transferred from the point of im-mergence of the dowel from the joint face throughout the slab, and thus reduce the stress on the, con,- crete at the point where the dowelmeets ,the joint to less than half of what it would otherw else. Thus breakage of the concrete around the, dowel at the Joint a e is bstantiall les ned. and injuries to the slab are, greatly reduced.

e U s tr u s 1 .1 t esse a e? from the joint face, at least 65% of these stres being transferred from the portion of the dowel adjacent the joint into the material remote, from the joint face and above and below the dowel.

Furthermore, the use of such an arrangement makes it possible to use a comparatively short dowel. This dowel should be less in length than the thickness of the concrete slab. Because of; the fact that the stresses are transferred immee diately to the face of the joint through aqlarge area of the slab, the need for extending the dowel into the slab is eliminated. On the other hand, the supporting and stress distributing members engage the dowel directly with their three point contact, so that the stress on, the dowel is directly transferred into the material of the roadway.

The units so shown are very simple to make, re: quiring only the bending of the two U-shaped: members and the welding at two points. Because Of the fact that the three, point suspension. is provided, it is unnecessary that the parts he set together with extreme care, so that high accuracy in the assembly is not necessary. 'I'heexpense of manufacture of such a part is therefore extremely low.

Fig. 6 shows a modified form. of the invention. In 1 th bars. are fo med of wire provided with deformed portions. For example, upper member- 22 and lower member 2.4: are formed of a wire provided with circular ribs 25. It may also be desirable to obtain additional anchorage by hav-- ing horizontally bent extensions 28 on the upper members 22 and upwardly bentextensions 30!.o'n lower members 24. The dowel 8 fits between the members in the same manner as in Fig. 1.

Figs. 7 to 10 show the use of a somewhat modified unit in the production of a contraction joint in a concrete roadway. In producing such a joint, there is used a unit having, in addition to the parts previously described, short bars '31 Welded on the bight ends of upper membersul'. "I

provide also a joint forming member composed of a bar 32 having downward projections 34. These projections are provided with notches 36 spaced by intervals corresponding to the desired spacing of the dowels along the joint. Extensions 34 lie between the two supports. When the parts are assembled as shown in Fig. 7, the self adjustment of the dowel causes the ends of members 4 to engage against the extensions 34, so as to clamp the bar 32 between them. At the same time, the lower ends of the extensions are limited in their movement by bars 3!, which are longer than the width of notches 36. The unit is then sufliciently steady so that it will not be disturbed during the pouring of the concrete.

When this unit has been set upon a subgrade 4|, the concrete is poured up to the top of the side forms 4. When the concrete has set sufficiently, the bar 32 is lifted partly out of the concrete by means of the engagement of levers 42 beneath buttons 44 at the ends of bar 32. The bar is lifted to the position shown in Fig. 10, and is then used as a guide for an edge forming tool 45 which is run across the joint on each side of the bar 32 to round off the corner as at 46. After this is done, the bar 32 is removed and slab, as is well known, will crack along the joint as at 48.

Figs. 11 to 14 show the use of units such as shown in Fig. 1 in producing an expansion joint. For this purpose, there is provided a filler strip 50 formed of a suitable resilient material, and a shield 52 which slides over the upper part of the filler strip. This shield is provided with downwardly opening notches 54 at the desired spacing of the dowels, and the filler strip has dowel receiving holes at the same spacing. In forming a joint, a substantial number of the dowel units are assembled with the shield and. filler strip, the units being if necessary connected by means of bars 56 to which the legs of parts 4 are welded or otherwise connected, these bars extending across the length of the joint.

As will be noted in Fig. 11, when the unit so formed is placed on a roadway, the inner ends of members 4 tend to move towards each other to clamp shield 52 so that the unit is securely positioned on the subgrade.

After the concrete has been poured and has set sufiiciently, the shield 52 is removed by means of levers 58 engaging in holes 60 in the ends of the frame. When the shield has been removed, a wooden bar 62 is applied on top of the filler strip 50 and is secured thereto by nails 84. Then an edge shaping tool 45 is passed across the joint on both sides, using the bar 62 as a guide, to form rounded corners 46.

In an expansion joint of this type, it may be desirable to have the dowel on one side of the joint entering into an expansion cap 66. However, the dowel supporting units engage the dowel itself directly and not through the expansion cap. The expansion cap may be previously partially filled with grease in accordance with the usual practice.

While I have described herein some improvements of my invention, I wish it to be understood that I do not intend to limit myself thereby except within the scope of the claims hereto or hereinafter appended.

I claim:

1. A device for use in conjunction with road joint dowels, comprising two generally U-shaped metal members lying substantially in planes intersecting at an angle along a line close to the bights of the two members but slightly spaced from said bights in the direction of the free ends of the legs, the bights of the members forming between them an opening of a size to receive a dowel, the bight of one member having a smaller radius of curvature than that of the other member, the outside of the legs of the member having the bight of smaller radius being secured to the inside of the legs of the other member at the intersection.

2. In a dowel unit for road joints including a dowel and supporting means for each side thereof, each of said supporting means comprising two generally U-shaped metal members lying substantially in planes intersecting at an angle along a line close to the bights of the two members and adjacent the central portion of the dowel, one of said members being inclined rearwardly and upwardly and the other being inclined rearwardly and downwardly away from the central portion of the dowel to form a support for one side thereof, the members being secured to one another at the intersection and the bights of the members forming between them an opening receiving the dowel, said dowel being round in cross-section, the bight of the upwardly inclined member having a radius of curvature less than, and the bight of the downwardly inclined member having a radius of curvature greater than, the radius of cross-section of the dowel.

3. A device for use in conjunction with road joint dowels comprising two generally U-shaped metal members lying substantially in planes intersecting at an angle along a line close to the bights of the two members but slightly spaced from said bights in the direction of the free ends of the legs, the outsides of the legs of one of the members being secured to the insides of the legs of the other member at the intersection, the bights of the members forming between them an opening of a size to receive a dowel.

4. A device as claimed in claim 3 in which the legs of said members are divergent.

WILLIAM S. GODWIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,585,571 Swanson May 18, 1926 1,592,157 Reynolds July 13, 1926 1,753,523 Matthews Apr. 8, 1930 1,907,477 Bauman May 9, 1933 1,917,529 Lampert July 11, 1933 1,969,884 Heltzel Aug. 14, 1934 2,032,814 Robertson Mar. 3, 1936 2,043,367 Bitney June 9, 1936 2,082,978 Robertson June 8, 1937 2,133,553 Lord Oct. 18, 1938 2,148,595 Ulrich Feb. 28, 1939 2,152,751 Schulz Apr. 4, 1939 2,207,085 Brickman July 9, 1940 2,256,930 Willard Sept. 23, 1941 2,261,602 Yoemens Nov. 14, 1941 2,299,670 Westcott Oct. 20, 19 2 2,323,026 Geyer June 29, 1943 2,365,550 Heltzel Dec. 19, 1944 2,371,290 Heltzel Mar. 13, 1945 2,486,527 Hellberg Nov. 1, 1949 2,509,180 Yoemens May 23, 1950 

